I think you can also pay online or with the app Reservation. Gov

When you first drive onto property, before the first designated sites, there is a Dropbox with envelopes for the payment. When we were there in Sep 2022, many of the envelopes had been "water-damaged" but some were still usable. We wrote a check for the fee and simply deposited in Dropbox.

Drop box. Put cash and your info in an envelope then put in box.

Cash or Check deposited in an envelope at the pay station. There is a host present seasonally. I’m not sure when they’re there, but he was leaving shortly after we were there in April.